DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 DAC121S101/DAC121S101Q 12-Bit Micro Power, RRO Digital-to-Analog Converter Check for Samples: DAC121S101 FEATURES DESCRIPTION * The DAC121S101 is a full-featured, general purpose 12-bit voltage-output digital-to-analog converter (DAC) that can operate from a single +2.7V to 5.5V supply and consumes just 177 A of current at 3.6 Volts. The on-chip output amplifier allows rail-to-rail output swing and the three wire serial interface operates at clock rates up to 30 MHz over the specified supply voltage range and is compatible with standard SPITM, QSPI, MICROWIRE and DSP interfaces. Competitive devices are limited to 20 MHz clock rates at supply voltages in the 2.7V to 3.6V range. 1 23 * * * * * * * * DAC121S101Q is AEC-Q100 Grade 1 qualified and is manufactured on an Automotive Grade Flow. Guaranteed Monotonicity Low Power Operation Rail-to-Rail Voltage Output Power-on Reset to Zero Volts Output Wide Temperature Range of -40C to +125C Wide Power Supply Range of +2.7V to +5.5V Small Packages Power Down Feature APPLICATIONS * * * * * Battery-Powered Instruments Digital Gain and Offset Adjustment Programmable Voltage & Current Sources Programmable Attenuators Automotive The supply voltage for the DAC121S101 serves as its voltage reference, providing the widest possible output dynamic range. A power-on reset circuit ensures that the DAC output powers up to zero volts and remains there until there is a valid write to the device. A power-down feature reduces power consumption to less than a microWatt. The low power consumption and small packages of the DAC121S101 make it an excellent choice for use in battery operated equipment. The DAC121S101 is a direct replacement for the AD5320 and the DAC7512 and is one of a family of pin compatible DACs, including the 8-bit DAC081S101 and the 10-bit DAC101S101. The DAC121S101 operates over the extended industrial temperature range of -40C to +105C while the DAC121S101Q operates over the Grade 1 automotive temperature range of -40C to +125C. The DAC121S101 is available in a 6-lead SOT and an 8-lead VSSOP and the DAC121S101Q is available in the 6-lead SOT only. Table 1. Key Specifications VALUE UNIT Resolution 12 bits DNL +0.25, -0.15 LSB (typ) Output Settling Time 8 s (typ) Zero Code Error 4 mV (typ) Full-Scale Error -0.06 %FS (typ) Normal Mode 0.64mW (3.6V) / 1.43mW (5.5V) typ Pwr Down Mode 0.14W (3.6V) / 0.39W (5.5V) typ Power Consumption 1 2 3 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. SPI is a trademark of Motorola, Inc.. All other trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright (c) 2005-2013, Texas Instruments Incorporated DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com Pin Configuration VOUT 1 6 SYNC VA 1 8 GND NC NC 2 7 3 6 DIN SCLK VOUT 4 5 SYNC SOT GND 2 5 SCLK VA 3 4 DIN VSSOP Block Diagram VA GND POWER-ON RESET DAC121S101 REF(+) REF(-) DAC REGISTER 12 12-BIT DAC BUFFER VOUT 12 POWER-DOWN CONTROL LOGIC INPUT CONTROL LOGIC SYNC SCLK 1k 100k DIN Pin Functions Pin Descriptions SOT (SOT-23) Pin No. VSSOP Pin No. Symbol 1 4 VOUT DAC Analog Output Voltage. 2 8 GND Ground reference for all on-chip circuitry. 3 1 VA Power supply and Reference input. Should be decoupled to GND. 4 7 DIN Serial Data Input. Data is clocked into the 16-bit shift register on the falling edges of SCLK after the fall of SYNC. 5 6 SCLK Serial Clock Input. Data is clocked into the input shift register on the falling edges of this pin. 6 5 SYNC Frame synchronization input for the data input. When this pin goes low, it enables the input shift register and data is transferred on the falling edges of SCLK. The DAC is updated on the 16th clock cycle unless SYNC is brought high before the 16th clock, in which case the rising edge of SYNC acts as an interrupt and the write sequence is ignored by the DAC. 2, 3 NC Description No Connect. There is no internal connection to these pins. These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 2 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 Absolute Maximum Ratings (1) (2) Supply Voltage, VA 6.5V -0.3V to (VA + 0.3V) Voltage on any Input Pin Input Current at Any Pin Package Input Current (3) 10 mA (3) 20 mA Power Consumption at TA = 25C See (4) (5) ESD Susceptibility Human Body Model Machine Model 2500V 250V Soldering Temperature, Infrared, 10 Seconds (6) 235C -65C to +150C Storage Temperature (1) (2) (3) (4) (5) (6) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. All voltages are measured with respect to GND = 0V, unless otherwise specified When the input voltage at any pin exceeds the power supplies (that is, less than GND, or greater than VA), the current at that pin should be limited to 10 mA. The 20 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 10 mA to two. The absolute maximum junction temperature (TJMAX) for this device is 150C. The maximum allowable power dissipation is dictated by TJMAX, the junction-to-ambient thermal resistance (JA), and the ambient temperature (TA), and can be calculated using the formula PDMAX = (TJMAX - TA) / JA. The values for maximum power dissipation will be reached only when the device is operated in a severe fault condition (e.g., when input or output pins are driven beyond the power supply voltages, or the power supply polarity is reversed). Obviously, such conditions should always be avoided. Human body model is 100 pF capacitor discharged through a 1.5 k resistor. Machine model is 220 pF discharged through ZERO Ohms. See the section entitled "Surface Mount" found in any post 1986 National Semiconductor Linear Data Book for methods of soldering surface mount devices. Operating Ratings (1) (2) Operating Temperature Range DAC121S101 -40C TA +105C DAC121S101Q -40C TA +125C Supply Voltage, VA Any Input Voltage +2.7V to 5.5V (3) -0.1 V to (VA + 0.1 V) Output Load 0 to 1500 pF SCLK Frequency (1) (2) (3) Up to 30 MHz Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. All voltages are measured with respect to GND = 0V, unless otherwise specified The analog inputs are protected as shown below. Input voltage magnitudes up to VA + 300 mV or to 300 mV below GND will not damage this device. However, errors in the conversion result can occur if any input goes above VA or below GND by more than 100 mV. For example, if VA is 2.7VDC, ensure that -100mV input voltages 2.8VDC to ensure accurate conversions. I/O TO INTERNAL CIRCUITRY GND Package Thermal Resistances Package JA 8-Lead VSSOP 240C/W 6-Lead SOT 250C/W Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 3 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com Electrical Characteristics The following specifications apply for VA = +2.7V to +5.5V, RL = 2k to GND, CL = 200 pF to GND, fSCLK = 30 MHz, input code range 48 to 4047. Boldface limits apply for TMIN TA TMAX: all other limits TA = 25C, unless otherwise specified. Limits (1) Units (Limits) Resolution 12 Bits (min) Monotonicity 12 Bits (min) 2.6 8 LSB (max) +0.25 +1.0 LSB (max) -0.15 -0.7 LSB (min) 0.11 0.5 LSB (max) Symbol Parameter Conditions Typical (1) STATIC PERFORMANCE INL Integral Non-Linearity DNL Differential Non-Linearity Over Decimal codes 48 to 4047 VA = 2.7V to 5.5V VA = 4.5V to 5.5V (2) ZE Zero Code Error IOUT = 0 +4 +15 mV (max) FSE Full-Scale Error IOUT = 0 -0.06 -1.0 %FSR (max) GE Gain Error All ones Loaded to DAC register -0.10 1.0 %FSR -20 V/C VA = 3V -0.7 ppm/C VA = 5V -1.0 ppm/C ZCED TC GE Zero Code Error Drift Gain Error Tempco OUTPUT CHARACTERISTICS Output Voltage Range ZCO FSO Zero Code Output Full Scale Output Maximum Load Capacitance Output Short Circuit Current V (min) V (max) VA = 3V, IOUT = 10 A 1.8 mV VA = 3V, IOUT = 100 A 5.0 mV VA = 5V, IOUT = 10 A 3.7 mV VA = 5V, IOUT = 100 A 5.4 mV VA = 3V, IOUT = 10 A 2.997 V VA = 3V, IOUT = 100 A 2.990 V VA = 5V, IOUT = 10 A 4.995 V VA = 5V, IOUT = 100 A 4.992 V RL = 1500 pF RL = 2k 1500 pF 1.3 Ohm VA = 5V, VOUT = 0V, Input code = FFFh -63 mA VA = 3V, VOUT = 0V, Input code = FFFh -50 mA VA = 5V, VOUT = 5V, Input code = 000h 74 mA VA = 3V, VOUT = 3V, Input code = 000h 53 mA DC Output Impedance IOS 0 VA (2) LOGIC INPUT IIN Input Current VIL VIH CIN (1) (2) 4 (2) Input Low Voltage (2) Input High Voltage (2) Input Capacitance (2) 1 A (max) VA = 5V 0.8 V (max) VA = 3V 0.5 V (max) VA = 5V 2.4 V (min) VA = 3V 2.1 V (min) 3 pF (max) Typical figures are at TJ = 25C, and represent most likely parametric norms. Test limits are guaranteed to TI's AOQL (Average Outgoing Quality Level). This parameter is guaranteed by design and/or characterization and is not tested in production. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 Electrical Characteristics (continued) The following specifications apply for VA = +2.7V to +5.5V, RL = 2k to GND, CL = 200 pF to GND, fSCLK = 30 MHz, input code range 48 to 4047. Boldface limits apply for TMIN TA TMAX: all other limits TA = 25C, unless otherwise specified. Symbol Parameter Conditions Typical Limits (1) Units (Limits) (1) POWER REQUIREMENTS IA PC IOUT / IA (3) Normal Mode fSCLK = 30 MHz VA = 5.5V 260 312 A (max) VA = 3.6V 177 217 A (max) Normal Mode fSCLK = 20 MHz VA = 5.5V 224 279 A (max) VA = 3.6V 158 197 A (max) Normal Mode fSCLK = 0 VA = 5.5V 153 A (max) VA = 3.6V 118 A (max) All PD Modes, fSCLK = 30 MHz VA = 5.0V 84 A (max) VA = 3.0V 42 A (max) All PD Modes, fSCLK = 20 MHz VA = 5.0V 56 A (max) VA = 3.0V 28 All PD Modes, fSCLK = 0 (3) VA = 5.5V 0.07 1.0 VA = 3.6V 0.04 1.0 A (max) Normal Mode fSCLK = 30 MHz VA = 5.5V 1.43 1.72 mW (max) VA = 3.6V 0.64 0.78 mW (max) Normal Mode fSCLK = 20 MHz VA = 5.5V 1.23 1.53 mW (max) VA = 3.6V 0.57 0.71 mW (max) Normal Mode fSCLK = 0 VA = 5.5V 0.84 W (max) VA = 3.6V 0.42 W (max) All PD Modes, fSCLK = 30 MHz VA = 5.0V 0.42 W (max) VA = 3.0V 0.13 W (max) All PD Modes, fSCLK = 20 MHz VA = 5.0V 0.28 W (max) VA = 3.0V 0.08 All PD Modes, fSCLK = 0 (3) VA = 5.5V 0.39 5.5 W (max) VA = 3.6V 0.14 3.6 W (max) Supply Current (output unloaded) Power Consumption (output unloaded) Power Efficiency ILOAD = 2mA A (max) A (max) W (max) VA = 5V 91 % VA = 3V 94 % This parameter is guaranteed by design and/or characterization and is not tested in production. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 5 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com A.C. and Timing Characteristics The following specifications apply for VA = +2.7V to +5.5V, RL = 2k to GND, CL = 200 pF to GND, fSCLK = 30 MHz, input code range 48 to 4047. Boldface limits apply for TMIN TA TMAX: all other limits TA = 25C, unless otherwise specified. Symbol fSCLK Parameter Conductions Typical SCLK Frequency ts Output Voltage Settling Time SR (1) Units (Limits) 30 MHz (max) 10 s (max) 400h to C00h code change, RL = 2k CL 200 pF 8 CL = 500 pF 12 s 00Fh to FF0h code change, RL = 2k CL 200 pF 8 s CL = 500 pF 12 s 1 V/s 12 nV-sec Output Slew Rate Glitch Impulse Limits Code change from 800h to 7FFh Digital Feedthrough 0.5 nV-sec VA = 5V 6 s VA = 3V 39 s tWU Wake-Up Time 1/fSCLK SCLK Cycle Time 33 ns (min) tH SCLK High time 5 13 ns (min) tL SCLK Low Time 5 13 ns (min) tSUCL Set-up Time SYNC to SCLK Rising Edge -15 0 ns (min) tSUD Data Set-Up Time 2.5 5 ns (min) tDHD Data Hold Time 2.5 4.5 ns (min) tCS SCLK fall to rise of SYNC VA = 5V 0 3 ns (min) VA = 3V -2 1 ns (min) 2.7 VA 3.6 9 20 ns (min) 3.6 VA 5.5 5 10 ns (min) tSYNC (1) SYNC High Time This parameter is guaranteed by design and/or characterization and is not tested in production. Specification Definitions DIFFERENTIAL NON-LINEARITY (DNL) is the measure of the maximum deviation from the ideal step size of 1 LSB, which is VREF / 4096 = VA / 4096. DIGITAL FEEDTHROUGH is a measure of the energy injected into the analog output of the DAC from the digital inputs when the DAC outputs are not updated. It is measured with a full-scale code change on the data bus. FULL-SCALE ERROR is the difference between the actual output voltage with a full scale code (FFFh) loaded into the DAC and the value of VA x 4095 / 4096. GAIN ERROR is the deviation from the ideal slope of the transfer function. It can be calculated from Zero and Full-Scale Errors as GE = FSE - ZE, where GE is Gain error, FSE is Full-Scale Error and ZE is Zero Error. GLITCH IMPULSE is the energy injected into the analog output when the input code to the DAC register changes. It is specified as the area of the glitch in nanovolt-seconds. INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a straight line through the input to output transfer function. The deviation of any given code from this straight line is measured from the center of that code value. The end point method is used. INL for this product is specified over a limited range, per the Electrical Characteristics. LEAST SIGNIFICANT BIT (LSB) is the bit that has the smallest value or weight of all bits in a word. This value is LSB = VREF / 2n (1) where VREF is the supply voltage for this product, and "n" is the DAC resolution in bits, which is 12 for the DAC121S101. MAXIMUM LOAD CAPACITANCE is the maximum capacitance that can be driven by the DAC with output stability maintained. 6 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 MONOTONICITY is the condition of being monotonic, where the DAC has an output that never decreases when the input code increases. MOST SIGNIFICANT BIT (MSB) is the bit that has the largest value or weight of all bits in a word. Its value is 1/2 of VA. POWER EFFICIENCY is the ratio of the output current to the total supply current. The output current comes from the power supply. The difference between the supply and output currents is the power consumed by the device without a load. SETTLING TIME is the time for the output to settle to within 1/2 LSB of the final value after the input code is updated. WAKE-UP TIME is the time for the output to settle to within 1/2 LSB of the final value after the device is commanded to the active mode from any of the power down modes. ZERO CODE ERROR is the output error, or voltage, present at the DAC output after a code of 000h has been entered. Transfer Characteristic FSE 4095 x VA 4096 GE = FSE - ZE FSE = GE + ZE OUTPUT VOLTAGE ZE 0 0 4095 DIGITAL INPUT CODE Figure 1. Input / Output Transfer Characteristic Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 7 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com Timing Diagram SCLK 1 tSUCL 13 14 15 16 tL tH tCS | tSYNC 2 | | 1 / fSCLK | SYNC DB15 DB0 | DIN | | tDHD tSUD Figure 2. DAC121S101 Timing 8 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 Typical Performance Characteristics fSCLK = 30 MHz, TA = 25C, Input Code Range 48 to 4047, unless otherwise stated DNL at VA = 3.0V DNL at VA = 5.0V Figure 3. Figure 4. INL at VA = 3.0V INL at VA = 5.0V Figure 5. Figure 6. TUE at VA = 3.0V TUE at VA = 5.0V Figure 7. Figure 8. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 9 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) fSCLK = 30 MHz, TA = 25C, Input Code Range 48 to 4047, unless otherwise stated 10 DNL vs. VA INL vs. VA Figure 9. Figure 10. 3V DNL vs. fSCLK 5V DNL vs. fSCLK Figure 11. Figure 12. 3V DNL vs. Clock Duty Cycle 5V DNL vs. Clock Duty Cycle Figure 13. Figure 14. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 Typical Performance Characteristics (continued) fSCLK = 30 MHz, TA = 25C, Input Code Range 48 to 4047, unless otherwise stated 3V DNL vs. Temperature 5V DNL vs. Temperature Figure 15. Figure 16. 3V INL vs. fSCLK 5V INL vs. fSCLK Figure 17. Figure 18. 3V INL vs. Clock Duty Cycle 5V INL vs. Clock Duty Cycle Figure 19. Figure 20. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 11 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) fSCLK = 30 MHz, TA = 25C, Input Code Range 48 to 4047, unless otherwise stated 12 3V INL vs. Temperature 5V INL vs. Temperature Figure 21. Figure 22. Zero Code Error vs. fSCLK Zero Code Error vs. Clock Duty Cycle Figure 23. Figure 24. Zero Code Error vs. Temperature Full-Scale Error vs. fSCLK Figure 25. Figure 26. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 Typical Performance Characteristics (continued) fSCLK = 30 MHz, TA = 25C, Input Code Range 48 to 4047, unless otherwise stated Full-Scale Error vs. Clock Duty Cycle Full-Scale Error vs. Temperature Figure 27. Figure 28. Supply Current vs. VA Supply Current vs. Temperature Figure 29. Figure 30. 5V Glitch Response Power-On Reset Figure 31. Figure 32. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 13 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) fSCLK = 30 MHz, TA = 25C, Input Code Range 48 to 4047, unless otherwise stated 3V Wake-Up Time 5V Wake-Up Time Figure 33. Figure 34. FUNCTIONAL DESCRIPTION DAC SECTION The DAC121S101 is fabricated on a CMOS process with an architecture that consists of switches and a resistor string that are followed by an output buffer. The power supply serves as the reference voltage. The input coding is straight binary with an ideal output voltage of: VOUT = VA x (D / 4096) (2) where D is the decimal equivalent of the binary code that is loaded into the DAC register and can take on any value between 0 and 4095. RESISTOR STRING The resistor string is shown in Figure 35. This string consists of 4096 equal valued resistors with a switch at each junction of two resistors, plus a switch to ground. The code loaded into the DAC register determines which switch is closed, connecting the proper node to the amplifier. This configuration guarantees that the DAC is monotonic. 14 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 VA R R R To Output Amplifier R R Figure 35. DAC Resistor String OUTPUT AMPLIFIER The output buffer amplifier is a rail-to-rail type, providing an output voltage range of 0V to VA. All amplifiers, even rail-to-rail types, exhibit a loss of linearity as the output approaches the supply rails (0V and VA, in this case). For this reason, linearity is specified over less than the full output range of the DAC. The output capabilities of the amplifier are described in the Electrical Characteristics. SERIAL INTERFACE The three-wire interface is compatible with SPI, QSPI and MICROWIRE, as well as most DSPs. See the Timing Diagram for information on a write sequence. A write sequence begins by bringing the SYNC line low. Once SYNC is low, the data on the DIN line is clocked into the 16-bit serial input register on the falling edges of SCLK. On the 16th falling clock edge, the last data bit is clocked in and the programmed function (a change in the mode of operation and/or a change in the DAC register contents) is executed. At this point the SYNC line may be kept low or brought high. In either case, it must be brought high for the minimum specified time before the next write sequence as a falling edge of SYNC can initiate the next write cycle. Since the SYNC and DIN buffers draw more current when they are high, they should be idled low between write sequences to minimize power consumption. INPUT SHIFT REGISTER The input shift register, Figure 36, has sixteen bits. The first two bits are "don't cares" and are followed by two bits that determine the mode of operation (normal mode or one of three power-down modes). The contents of the serial input register are transferred to the DAC register on the sixteenth falling edge of SCLK. See Timing Diagram, Figure 2. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 15 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com DB15 (MSB) X X DB0 (LSB) PD1 PD0 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 DATA BITS 0 0 1 1 0 Normal Operation 1 1 k:to GND 0 100 k: to GND 1 High Impedance Power-Down Modes Figure 36. Input Register Contents Normally, the SYNC line is kept low for at least 16 falling edges of SCLK and the DAC is updated on the 16th SCLK falling edge. However, if SYNC is brought high before the 16th falling edge, the shift register is reset and the write sequence is invalid. The DAC register is not updated and there is no change in the mode of operation or in the output voltage. POWER-ON RESET The power-on reset circuit controls the output voltage during power-up. Upon application of power the DAC register is filled with zeros and the output voltage is 0 Volts and remains there until a valid write sequence is made to the DAC. POWER-DOWN MODES The DAC121S101 has four modes of operation. These modes are set with two bits (DB13 and DB12) in the control register. Table 2. Modes of Operation DB13 DB12 0 0 Normal Operation Operating Mode 0 1 Power-Down with 1k to GND 1 0 Power-Down with 100k to GND 1 1 Power-Down with Hi-Z When both DB13 and DB12 are 0, the device operates normally. For the other three possible combinations of these bits the supply current drops to its power-down level and the output is pulled down with either a 1k or a 100K resistor, or is in a high impedance state, as described in Table 2. The bias generator, output amplifier, the resistor string and other linear circuitry are all shut down in any of the power-down modes. However, the contents of the DAC register are unaffected when in power-down, so when coming out of power down the output voltage returns to the same voltage it was before entering power down. Minimum power consumption is achieved in the power-down mode with SCLK disabled and SYNC and DIN idled low. The time to exit power-down (Wake-Up Time) is typically tWU sec as stated in the A.C. and Timing Characteristics Table. APPLICATION INFORMATION DSP/MICROPROCESSOR INTERFACING The simplicity of the DAC121S101 implies ease of use. However, it is important to recognize that any data converter that utilizes its supply voltage as its reference voltage will have essentially zero PSRR (Power Supply Rejection Ratio). Therefore, it is necessary to provide a noise-free supply voltage to the device. Interfacing the DAC121S101 to microprocessors and DSPs is quite simple. The following guidelines are offered to hasten the design process. 16 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 ADSP-2101/ADSP2103 Interfacing Figure 37 shows a serial interface between the DAC121S101 and the ADSP-2101/ADSP2103. The DSP should be set to operate in the SPORT Transmit Alternate Framing Mode. It is programmed through the SPORT control register and should be configured for Internal Clock Operation, Active Low Framing and 16-bit Word Length. Transmission is started by writing a word to the Tx register after the SPORT mode has been enabled. ADSP-2101/ ADSP2103 TFS DT SCLK DAC121S101 SYNC DIN SCLK Figure 37. ADSP-2101/2103 Interface 80C51/80L51 Interface A serial interface between the DAC121S101 and the 80C51/80L51 microcontroller is shown in Figure 38. The SYNC signal comes from a bit-programmable pin on the microcontroller. The example shown here uses port line P3.3. This line is taken low when data is to transmitted to the DAC121S101. Since the 80C51/80L51 transmits 8bit bytes, only eight falling clock edges occur in the transmit cycle. To load data into the DAC, the P3.3 line must be left low after the first eight bits are transmitted. A second write cycle is initiated to transmit the second byte of data, after which port line P3.3 is brought high. The 80C51/80L51 transmit routine must recognize that the 80C51/80L51 transmits data with the LSB first while the DAC121S101 requires data with the MSB first. 80C51/80L51 P3.3 DAC121S101 SYNC TXD SCLK RXD DIN Figure 38. 80C51/80L51 Interface 68HC11 Interface A serial interface between the DAC121S101 and the 68HC11 microcontroller is shown in Figure 39. The SYNC line of the DAC121S101 is driven from a port line (PC7 in the figure), similar to the 80C51/80L51. The 68HC11 should be configured with its CPOL bit as a zero and its CPHA bit as a one. This configuration causes data on the MOSI output to be valid on the falling edge of SCLK. PC7 is taken low to transmit data to the DAC. The 68HC11 transmits data in 8-bit bytes with eight falling clock edges. Data is transmitted with the MSB first. PC7 must remain low after the first eight bits are transferred. A second write cycle is initiated to transmit the second byte of data to the DAC, after which PC7 should be raised to end the write sequence. 68HC11 DAC121S101 PC7 SCK MOSI SYNC SCLK DIN Figure 39. 68HC11 Interface Microwire Interface Figure 40 shows an interface between a Microwire compatible device and the DAC121S101. Data is clocked out on the rising edges of the SCLK signal. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 17 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com MICROWIRE DEVICE DAC121S101 CS SYNC SK SCLK SO DIN Figure 40. Microwire Interface USING REFERENCES AS POWER SUPPLIES Recall the need for a quiet supply source for devices that use their power supply voltage as a reference voltage. Since the DAC121S101 consumes very little power, a reference source may be used as the supply voltage. The advantages of using a reference source over a voltage regulator are accuracy and stability. Some low noise regulators can also be used for the power supply of the DAC121S101. Listed below are a few power supply options for the DAC121S101. LM4130 The LM4130 reference, with its 0.05% accuracy over temperature, is a good choice as a power source for the DAC121S101. Its primary disadvantage is the lack of 3V and 5V versions. However, the 4.096V version is useful if a 0 to 4.095V output range is desirable or acceptable. Bypassing the LM4130 VIN pin with a 0.1F capacitor and the VOUT pin with a 2.2F capacitor will improve stability and reduce output noise. The LM4130 comes in a space-saving 5-pin SOT23. Input Voltage LM4130-4.1 C2 2.2 PF C1 0.1 PF DAC121S101 SYNC VOUT = 0V to 4.095V DIN SCLK Figure 41. The LM4130 as a power supply LM4050 Available with accuracy of 0.44%, the LM4050 shunt reference is also a good choice as a power regulator for the DAC121S101. It does not come in a 3 Volt version, but 4.096V and 5V versions are available. It comes in a space-saving 3-pin SOT23. Input Voltage R VZ LM4050-4.1 or LM4050-5.0 0.47 PF DAC121S101 SYNC VOUT = 0V to 5V DIN SCLK Figure 42. The LM4050 as a power supply 18 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 The minimum resistor value in the circuit of Figure 42 should be chosen such that the maximum current through the LM4050 does not exceed its 15 mA rating. The conditions for maximum current include the input voltage at its maximum, the LM4050 voltage at its minimum, the resistor value at its minimum due to tolerance, and the DAC121S101 draws zero current. The maximum resistor value must allow the LM4050 to draw more than its minimum current for regulation plus the maximum DAC121S101 current in full operation. The conditions for minimum current include the input voltage at its minimum, the LM4050 voltage at its maximum, the resistor value at its maximum due to tolerance, and the DAC121S101 draws its maximum current. These conditions can be summarized as R(min) = ( VIN(max) - VZ(min) / (IA(min) + IZ(max)) (3) R(max) = ( VIN(min) - VZ(max) / (IA(max) + IZ(min) ) (4) and where VZ(min) and VZ(max) are the nominal LM4050 output voltages the LM4050 output tolerance over temperature, IZ(max) is the maximum allowable current through the LM4050, IZ(min) is the minimum current required by the LM4050 for proper regulation, IA(max) is the maximum DAC121S101 supply current, and IA(min) is the minimum DAC121S101 supply current. LP3985 The LP3985 is a low noise, ultra low dropout voltage regulator with a 3% accuracy over temperature. It is a good choice for applications that do not require a precision reference for the DAC121S101. It comes in 3.0V, 3.3V and 5V versions, among others, and sports a low 30 V noise specification at low frequencies. Since low frequency noise is relatively difficult to filter, this specification could be important for some applications. The LP3985 comes in a space-saving 5-pin SOT-23 and 5-bump DSBGA packages. Input Voltage LP3985 1 PF 0.1 PF 0.01 PF DAC121S101 SYNC VOUT = 0V to 5V DIN SCLK Figure 43. Using the LP3985 regulator An input capacitance of 1.0F without any ESR requirement is required at the LP3985 input, while a 1.0F ceramic capacitor with an ESR requirement of 5m to 500m is required at the output. Careful interpretation and understanding of the capacitor specification is required to ensure correct device operation. LP2980 The LP2980 is an ultra low dropout regulator with a 0.5% or 1.0% accuracy over temperature, depending upon grade. It is available in 3.0V, 3.3V and 5V versions, among others. Input Voltage VIN ON / OFF LP2980 VOUT 1 PF DAC121S101 SYNC VOUT = 0V to 5V DIN SCLK Figure 44. Using the LP2980 regulator Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 19 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com Like any low dropout regulator, the LP2980 requires an output capacitor for loop stability. This output capacitor must be at least 1.0F over temperature, but values of 2.2F or more will provide even better performance. The ESR of this capacitor should be within the range specified in the LP2980 data sheet. Surface-mount solid tantalum capacitors offer a good combination of small size and ESR. Ceramic capacitors are attractive due to their small size but generally have ESR values that are too low for use with the LP2980. Aluminum electrolytic capacitors are typically not a good choice due to their large size and have ESR values that may be too high at low temperatures. BIPOLAR OPERATION The DAC121S101 is designed for single supply operation and thus has a unipolar output. However, a bipolar output may be obtained with the circuit in Figure 45. This circuit will provide an output voltage range of 5 Volts. A rail-to-rail amplifier should be used if the amplifier supplies are limited to 5V. 10 pF R2 +5V +5V 10 PF + R1 - 0.1 PF 5V + DAC121S101 -5V SYNC VOUT DIN SCLK Figure 45. Bipolar Operation The output voltage of this circuit for any code is found to be VO = (VA x (D / 4096) x ((R1 + R2) / R1) - VA x R2 / R1) (5) where D is the input code in decimal form. With VA = 5V and R1 = R2, VO = (10 x D / 4096) - 5V (6) A list of rail-to-rail amplifiers suitable for this application are indicated in Table 3. Table 3. Some Rail-to-Rail Amplifiers AMP PKGS LMC7111 PDIP SOT-23 Typ VOS Typ ISUPPLY 0.9 mV 25 A LM7301 SOIC SOT-23 0.03 mV 620 A LM8261 SOT-23 0.7 mV 1 mA LAYOUT, GROUNDING, AND BYPASSING For best accuracy and minimum noise, the printed circuit board containing the DAC121S101 should have separate analog and digital areas. The areas are defined by the locations of the analog and digital power planes. Both of these planes should be located in the same board layer. There should be a single ground plane. A single ground plane is preferred if digital return current does not flow through the analog ground area. Frequently a single ground plane design will utilize a "fencing" technique to prevent the mixing of analog and digital ground current. Separate ground planes should only be utilized when the fencing technique is inadequate. The separate ground planes must be connected in one place, preferably near the DAC121S101. Special care is required to guarantee that digital signals with fast edge rates do not pass over split ground planes. They must always have a continuous return path below their traces. The DAC121S101 power supply should be bypassed with a 10F and a 0.1F capacitor as close as possible to the device with the 0.1F right at the device supply pin. The 10F capacitor should be a tantalum type and the 0.1F capacitor should be a low ESL, low ESR type. The power supply for the DAC121S101 should only be used for analog circuits. 20 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 DAC121S101 www.ti.com SNAS265I - JUNE 2005 - REVISED MARCH 2013 Avoid crossover of analog and digital signals and keep the clock and data lines on the component side of the board. The clock and data lines should have controlled impedances. Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 21 DAC121S101 SNAS265I - JUNE 2005 - REVISED MARCH 2013 www.ti.com REVISION HISTORY Changes from Revision H (March 2013) to Revision I * 22 Page Changed layout of National Data Sheet to TI format .......................................................................................................... 21 Submit Documentation Feedback Copyright (c) 2005-2013, Texas Instruments Incorporated Product Folder Links: DAC121S101 PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (C) Device Marking (4/5) DAC121S101CIMK NRND SOT DDC 6 1000 TBD Call TI Call TI -40 to 105 X61C DAC121S101CIMK/NOPB ACTIVE SOT DDC 6 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 105 X61C DAC121S101CIMKX/NOPB ACTIVE SOT DDC 6 3000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 105 X61C DAC121S101CIMM/NOPB ACTIVE VSSOP DGK 8 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 105 X60C DAC121S101CIMMX/NOPB ACTIVE VSSOP DGK 8 3500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM DAC121S101QCMK/NOPB ACTIVE SOT DDC 6 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 X61Q DAC121S101QCMKX/NOPB ACTIVE SOT DDC 6 3000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 X61Q X60C (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. 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OTHER QUALIFIED VERSIONS OF DAC121S101, DAC121S101-Q1 : * Automotive: DAC121S101-Q1 * Military: DAC121S101 NOTE: Qualified Version Definitions: * Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects * Military - QML certified for Military and Defense Applications Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant DAC121S101CIMK SOT DDC 6 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 DAC121S101CIMK/NOPB SOT DDC 6 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 SOT DDC 6 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 DAC121S101CIMM/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 DAC121S101QCMK/NOP B SOT DDC 6 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 DAC121S101QCMKX/NO PB SOT DDC 6 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 DAC121S101CIMKX/NOP B Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) DAC121S101CIMK SOT DDC 6 1000 210.0 185.0 35.0 DAC121S101CIMK/NOPB SOT DDC 6 1000 210.0 185.0 35.0 SOT DDC 6 3000 210.0 185.0 35.0 DAC121S101CIMM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 DAC121S101QCMK/NOPB SOT DDC 6 1000 210.0 185.0 35.0 SOT DDC 6 3000 210.0 185.0 35.0 DAC121S101CIMKX/NOP B DAC121S101QCMKX/NOP B Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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